A fluorescent, genetically-encoded voltage probe capable of resolving action potentials

PLoS One. 2012;7(9):e43454. doi: 10.1371/journal.pone.0043454. Epub 2012 Sep 6.


There is a pressing need in neuroscience for genetically-encoded, fluorescent voltage probes that can be targeted to specific neurons and circuits to allow study of neural activity using fluorescent imaging. We created 90 constructs in which the voltage sensing portion (S1-S4) of Ciona intestinalis voltage sensitive phosphatase (CiVSP) was fused to circularly permuted eGFP. This led to ElectricPk, a probe that is an order of magnitude faster (taus ~1-2 ms) than any currently published fluorescent protein-based voltage probe. ElectricPk can follow the rise and fall of neuronal action potentials with a modest decrease in fluorescence intensity (~0.7% ΔF/F). The probe has a nearly linear fluorescence/membrane potential response to both hyperpolarizing and depolarizing steps. This is the first probe based on CiVSP that captures the rapid movements of the voltage sensor, suggesting that voltage probes designed with circularly permuted fluorescent proteins may have some advantages.

Publication types

  • Research Support, American Recovery and Reinvestment Act
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials / physiology*
  • Amino Acid Sequence
  • Animals
  • Ciona intestinalis / enzymology*
  • Genes, Reporter*
  • Green Fluorescent Proteins / metabolism*
  • HEK293 Cells
  • Hippocampus / cytology
  • Hippocampus / physiology
  • Humans
  • Kinetics
  • Mice
  • Molecular Sequence Data
  • Neurons / physiology
  • Phosphoric Monoester Hydrolases / chemistry
  • Phosphoric Monoester Hydrolases / genetics*
  • Phosphoric Monoester Hydrolases / metabolism
  • Recombinant Fusion Proteins / metabolism


  • Recombinant Fusion Proteins
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • voltage-sensor-containing phosphatase, Ciona intestinalis
  • Phosphoric Monoester Hydrolases